I got the GTX 660 ti by ASUS, the OC (1085mhz)edition. When I try to overclock it crashes almost instantly. I know ever card is different and mine may only be able to clock to stock speeds and that's it. However the guy I got it from said it overclocked to 1200mhz on the core with screen shots and temps. But, for me if I even try to clock it to 105% power and +5 on the core clock it's ok. However any reasonable gain it crashes instantly. I tried increasing the power to 123% and the core at +30... And not even 1 second into the heaven benchmark and it's done.. Any suggestions? He said something about being able to raise the voltage. Is that the same thing as raising the "power" I mean it makes sense. But, it doesn't seem to be very stable still. Any takers? Any suggestions?

The bios is updated, and I'm using the Asus OC tweaker. I think my issue is my core clock will just not go much above stock. I can run about 300mhz over on my memory. But, my FPS increase isn't really a noticeable difference. I'll just keep it stock. I was only doing this to benchmark. For actual usage stock seems just fine.